Boiler-furnace draft-governor.



UNITED STATES Patented October 18, 1904.

,PATENT OFFICE..

BOILER-FURNACE DRAFT-GOVERNOR.

SPECIFICATION forming part of LettersiPatent N o..772,519, dated October18, 1904,

Application filed April Z0, 1903.

To @Mu/hom 711 may concern.-

Be it known that I, FDMUND B. KIRBY, a citizen of the United States,residing atRossl'and, in the Province of British Columbia and Dominionof Canada, yhave invented acertain new and useful Improvement inBoiler-Furnace Draft-Governors, of which the following is a full, clear,and exact description, reference being had to the accompanying drawings.

The invention relates to improvements in fluid-pressure regulatorsadapted especially for controlling the position of the draft appliancesof a steam-boiler furnace.

, The object of the invention is to provide such a device in aformwherein a spring shall offer increasing resistance to the movement ofthe parts after the vdesired minimum pressure `of steam in the boilerhas been reached, but in which it is not necessary to use a spring largeenough to oppose the movements of the parts before such minimum pressurehas been reached. In other words, the object of the invention is toprovide a device wherein the increased resistance of a small spring maybe l utilized instead of an excessively heavy and long spring.

In the drawings, Figure 1 is a side elevation, partly in section, of thebest-known embodiment ofthe invention; and Fig. 2 is a sectional plan onthe line 2 2.

Referring to the parts by letters, A repre# sents a support, to thelower end of which a'pot-cylinder B is secured, said cylinder beingconnected at its lower end with the steamspace of a boiler by means of atube Z).

C is the piston, which is movable with as little friction as possible insaid cylinder.'

D is the piston-rod, which is seated in a socket in the piston, fromwhich it extends upward through asuitable guide-lug a on the upper endof said support.

E represent a compression helical spring which surrounds the piston-rodand lies bei tween said lug a and a collar d, which is ad? justablysecured to the rod Dbelow this lug. Until the rod is forced upward bythe piston this spring is not subjected to much, if any, pressuretending to compress it. y,

Two shafts F and G are mounted on the support A. Small sheaves f and gare secured -upon these large sheaves.

Serial No. 153,564. (No model.)

to these shafts, respectively, and ropes or cords wound thereon areattached to a yoke cl2, which is in 'turn secured to the piston-rod. Twolarge sheaves f g are also attached to theseshafts, respectively, and aweight or weights K are suspend ed from cords 7c, wound It will be seenthat ifl the piston-rod moves upward it can only do so by raising theseweights and winding their cords upon the large sheaves. These weightsare of such size and the leverage produced by the difference in thesizes of the sheaves ff' g g' is such that these weights substantiallybalance the mechanism against the minimum pressure desired in theboiler. For example, if one desires to maintain in the boiler a pressurewhich shall vary between one hundred and one hundred and three poundsthese weights and the described parts may be arranged to balance onehundred pounds. The spring E will thereafter oppose the movement of thepiston and rod caused by the increaseof the steam-pressure.

It is obvious that a great variety of specific constructions may be madeembodying the generic construction hereinabove describednamely, aconstruction wherein weights are employed which are capable of balancingthe minimum pressure desired and a spring to resist the movementlinducedby a pressure in excess of the minimum pressure.

Having describedl my invention, I claim- 1. In a iiuidepressureregulator, the combination with a cylinder, of a piston, a rod securedthereto, a shaft rotatably mounted upon said cylinder, a sheave keyed tosaid shaft, a rope provided with a weight and passing around saidsheave, a smaller winding-drum also keyed to said shaft, an arm securedto said rod, a rope secured tosaid armand passing around said smalldrum, connections between said rod and the draft-damper, and a springfor resisting the pressure under said piston after the resistance causedby said weight is overcome, substantially as described.

2. Ina fluid-pressure regulator, the combination with a cylinder, of apiston, a rod secured thereto, a shaft rotatably mounted upon saidcylinder, a sheave keyed to said shaft, a rope provided with a weightand passing IOO around said sheave, a smaller Winding-drum also keyed tosaid shaft, an arm secured to said rod, a rope secured to said arm andpassing around said small drum, connections between said rod and thedraft-damper, a spring for resisting the pressure under said pistonafter the resistance caused by said weight is overcome, and means foradjusting the tension of said spring, su hstantially as described.

3. In a luid-pressure regulator, the combination With a cylinder, of apiston, a rod secured thereto, a shaft rotatably mounted upon saidcylinder, a sheave keyed to said shaft, a rope provided with a weightand passing around said sheave, a smaller Winding-drum also keyed tosaidshaft, an arm secured to said rod, a rope secured to said arm andpassing around said small drum, connections lietwcen said rod and thedraft-damper, a nut threaded onto said rod and a spring between said nutand a stationary portion of the device for resisting the pressure onsaid piston after the resistance caused by said eight thereon has beenovercome, substantially as described.

In testimony wher-col I hereunto allix my signature in the presence oitwo witnesses.

ICDNIUND B. KlllY.

Titnessesz C. V. JENKINS, H. J. DARBY.

